Electric impulse generator



Filed May 18, 1949 INVENTOR.

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Patented Nov. 11, 1952 ELECTRIC IMPULSE GENERATOR James L. Bisch, Valencia, Pa., assignor to Bisch Industries, Inc., Valencia, Pa., a. corporation of Pennsylvania Application May 18, 1949, Serial No. 93,923

3 Claims.

This invention relates to an electric impulse generator of the type having two opposed pairs of magnetic pole pieces housing an electric coil and a bar armature extending through the coil and adapted to contact on its opposite sides with pole pieces of opposite polarity, and then to be shifted to contact with the other pole pieces of the two pairs, such operation causing a reversal of the direction of flow of magnetic ux in the armature, and generating an impulse current in the circuit of the surrounding coil.

It is an object of the invention to provide such a device in a small, light and readily portable structure in which the mere swinging of the armature is effective to cause a sudden flow of current of proper capacity to discharge an ignition cap of a blasting charge.

In accomplishing the result, I provide in the device a condenser which may allow the current to accumulate on it the first portion of the movement of the armature and then discharge such current as the armature completes its movement, thus eliminating the high inductance peak which normally would ignite gaseous mixtures which may be present in a mine.

In my device, the coil, magnetic eld structure, and condenser within its case, are all mounted in very compact relationship. All these parts are preferably within an insulating envelope which has a yielding tubular neck which embraces an extension of the armature. The magnetism iiowing through the armature from pieces of opposite polarity maintains the armature normally in one of its extreme positions and the yielding neck of the envelope adapts itself thereto; then, when the device is to be operated the handle of the armature is suddenly swung to the opposite position, the yielding neck and cap of the envelope bending as the armature handle changes position.

The above-outlined features will be more fully described in connection with a preferred embodiment of my invention illustrated in the drawings.

In the drawings, Fig. 1 is a longitudinal central section through the device; Figs. 2 and 3 are sections taken on planes indicated by the correspondingly numbered lines in Fig. l; Fig. 4 is a perspective view illustrating the coil, iield structure and armature, and Fig. 5 is a diagram of the electric circuit.

My eld structure comprises two identical permanent magnets i0 and II which are disposed at opposite ends of a field structure. Engaging opposite poles of these magnets are two pieces I2 and I3 of soft iron or other material of high f iismagnetic susceptibility. Each of the eld pieces I2 and I3 has a pair of spaced pole faces as I4, I5 or I6 and I'I. Between the two poles in each of the pairs is a transverse recess occupied by an electric coil 2B. The coil is of substantially rectangular shape and surrounds a correspondingly shaped opening 2|, which registers with the spaces between opposed poles. These latter spaces flare away from the coil opening, that is downwardly and upwardly when the device is in the position of Fig. 2.

The armature 30 is a laminated steel member having a suitable extension 3| which has a socket 32 for receiving a detachable handle 33. The laminations may be held together by a layer of silver solder which extends across each end of the armature. This extension may conveniently be made of steel and may be soldered to the laminated member. The armature occupies the coil opening and extends above and below it so that below the coil one face of the armature will engage one of the pole pieces and above the coil the opposite face of the armature will engage another pole piece of opposite polarity.

If we assume, for instance, that the two pole pieces shown at the left of the armature, Fig. 2, are north poles, designated N and the two at the right south poles, designated S, then the armature standing in the position shown will receive magnetic flux from the lower north pole piece and such iiux will flow upwardly through the armature to the upper south pole piece. Now if the armature is thrown to the other position, indicated in broken lines in Fig. 2, the flux from the upper north pole piece flows downwardly through the armature to the lower south pole piece. It results therefrom that the mere shifting of the armature, changing the direction of magnetic iux therein, causes an impulse current through the coil, which is inductively connected with the armature.

To increase the quantity and suddenness of the delivered impulse current, I provide a condenser 35 which is connected across the two terminals ofthe coil. As the impulse current starts to form, resulting from the shifting of the armature, it rst causes an accumulation on the condenser, then as the impulse current increases with the further movement of the armature the overloaded condenser discharges and thus controls the current characteristics so as to eliminate the objectionable high inductance peak.

In Figs. 1 and 2, I have shown 4two binding posts 25 forming terminals of the coil. The condenser which is in a line 40, bridged across the terminal 3 lines, is contained in a cavity in a pair of casing members 4| and 42, of insulating material secured to the eld structure.

I have indicated the casing members I and 42 as held in place by bolts 50 passing through the members into the eld structure, there being preferably four of these bolts, two being shown in Fig. 2. llhave also shown four bolts 5I holding the magnets and` iield structure together in a rigid open frame embracing and holding the coil. This makes a very simple construction.

The armature, standing in theV space within.

the coil and between the pole pieces, is held in one position or the other by the magnetisrnof the engaged pole pieces. I'provide a cover for the device which is at once an insulator and a dust protector for the open space about the armature. This cover comprises a rubber envelope 60, rectangular in cross section, with an open bottom and with a top El which is closed except for ai tubular neck 62 through which the amature handle extends. The top portion El isshown as having a corrugated formation which allows. a. bending action of the-rubber-like ma terialwhenever the armature iss-wung from one position to another; Moreover, a close tting neck` portion 6.2y surrounds'the extension 3|, eX- ceptv for an opening through which the handle 33 may be inserted, and thus operates to keep the` interior of the device free from moisture, clust and foreign substances;

It isadvantageous to make the handlev 33 detachable from the armature so as to avoid the danger" of inadvertent operation of' the armature;v For convenience, the handle is provided with,a'-,ring'3:by^means of which it may be iastenedtothebelt'of an'operator. Thus the generator may' be` depositedV upon the ground until the' Wiring'Y operations are completed and then it may be operated wherever desired.

To' avoid chai-lng of' the' insulation for the coil consequent upon shifting of the armature, I: provide'a pair.` of guides which are'in the form of channel-shaped copperstrips 45V which extend through the space 2li and which are disposed'onthe oppositeV longitudinal edgesv of theV armature. Thesel strips have a close iitting'engagement with the interior portion of the coil andi are, therefore, stationary with respect to the coil; Thus, they operate to protect the coil i against abrasion.

My device is wellA adapted to comply with requirements of the U. S. Bureau of Mines in regard; to' the' operation of blasting machines in dusty or gassy coalimines, and to thisend it may generate af current suicient toy fire an electric blasting cap through '4i/f2' ohms resistance` while producing an.- arcwhich shall not last more than 35' miliseconds: To eiiect' this I- preferv to make the coil of. 22-gauge wire with 175, turns and I use Alnico V magnets. I prefer to use a condenser of 5' microfarad capacity at 50 working volts; have. found that operation of the device'. withoutthe condenser will produce an arc ofV objectionable'. duration, so as to cause an explosionr ina gassy Ycoal mine.

- It? will .be seen from the description given that I- have provided'a Very simple hand device, small andlight and of convenient shape and adapted td be' readily carried from place to place. It isi thoroughly insulated, andthe interior is protected from dust. Moreover', it is ready for immediate operation whenever desired, to give the requiredY impulse.. It isv only necessary to attach theconductoraas A and B, Fig..5, from the de- 4 tonating terminals C to the two binding posts 25 and then the device is ready for operation.

While I have described the invention as being suitable for use in discharging an ignition cap of a blasting charge, nevertheless it is not limited to such application but is intended for use wherever an electric impulse generator having the construction shown and claimed herein may be utilized.

I claim:

1. In an electric impulse generator, a field structure comprising a permanent magnet and two opposed and separated pairs of poles, there being a space between the poles of each pair, a coil occupying the last-mentioned space and having an internal passageway registering with the spacesv between poles, an armature occupying the coil and the spaces between the poles of opposite polarity, and having an extension thereon, a handle adapted to engage said extension. whereby theV armature may be swung back and forth between two eXtreme positions, and an envelope surrounding the field structure havinga yieldable cover with a tubular neck embracing thefextension said tubular neck having an opening for receiving said handle and said neck being yielding to allow the armature to shift between its extreme positions.

2. In an electric impulse generator, a field structure comprising a permanent magnet, two opposed and separated pairs of poles, there be'- ing a space between the poles of each pair, a coil occupying the last-mentioned space and having an internal passageway registering with the'spaces between the poles of opposite-polarity, an armature occupyingV the coil and the spaces between the poles oi oppositepolarity, a handle for said armature whereby the same may be swung back and forth between two extreme positions, an insulating casing secured to the iield structure beyond the region of the armature, means to limit the impulse current in the coil circuit to a predetermined safe value, said means comprising a condenser in said insulating cas-V ing and connected across the coil circuit, an envelope surrounding the iield structure and casing and having a corrugated top and a tubular neck embracing a portion of the armature, said top being yielding to allow the armature to shift between its eXtreme positions.

3L The combination of a permanent magnet and a pair oi extensions of material of magnetic susceptibility, each extension being secured to the magnet and each having two pole faces, the pole faces being spaced apart on each extensionand there being spaces between the opposed pole faces of the two extensions, a coil in the spaces between the pole pieces of the same extension, anarmature within the coil and engaging aY pole piece of one polarity on one side of the coil and a pole piece of the opposite polarity on the opposite side of the coil, said pole pieces being so arranged that the direction of magnetic ux through the armature when the armature is in one extreme position is opposite to that when the armature is in the other extreme position, a handle for moving said armature to either of said positions, a pair of insulating casing members mounted one on the other and both se cured to the held structure, said casing members having an internal cavity, a pair of binding posts carried by and external to the outer casingY member forming terminals for conductors leading from. the coil, means to limit the impulse current inV the coil circuit to a prede- 2,617,851 5 termined safe value, said means comprising a REFERENCES CITED condenser in the cavity of the Casings bridged The following references are of record in the across the lines from the coil to the binding me 'of this patent: posts, and an insulating cover extending around the eld structure and around the casings and 5 Y UNITED STATES PATENTS having a yielding tubular neck through which `Number Name Date the handle of the armature extends, said cover '1,334,095 Hill Mar. 16, 1920 having a laterally yieldable top portion which 1,466,209 Eichbaum Aug. 28, 1923 operates to allow the armature handle to swing 2,192,216 Woodruff Mar. 5, 1940 from the one extreme position to the other. l0 2,313,101 Stuart Mar. 9, 1943 2,326,696 Stoddard Aug. 10, 1948 JAMES L. BISCH. 2,471,741 Harris May 31, 1949 

